Electromagnetic shutter releasing device for a photographic camera

ABSTRACT

An electromagnetic shutter releasing device for a photographic camera utilizes, in combination with a permanent magnet, an electromagnet controlled by a pulse-like electric input to electromagnetically release a movable shutter blade from its normal stop position to a position for exposing a film. The polarity of the electric input to the electromagnet may be reversed so as to cause an interaction between the electromagnet and the permanent magnet and the resulting relative movement of the two magnets is detected to start and stop a shutter shaft drive motor. During a continuous shot, the drive motor may be maintained operative with the aid of the permanent magnet alone and without any electric input applied to the electromagnet.

United States Patent Hirata et al. Jan. 8, 1974 ELECTROMAGNETIC SHUTTER3,598,480 8/1971 Kubota 352/169 RELEASING DEVICE FOR A 3,576,362 4/1971Mayr 352/169 et a]. [75] Inventors: Noritsugu Hirata, Yokohama; PrimaryExaminer samuel S Matthews fs gg Taklgawa Tokyo both of AssistantExaminer-Russell E. Adams, J r.

p Attorney-Joseph M. Firzpa [73] Assignee: Canon Kabushiki Kaisha,Tokyo,

Japan [57] ABSTRACT [22] Filed: Oct. 22, 1971 A l t h H l d f h n eectromagne s u er re easing evice or a p o- [211 Appl' l91609 tographiccamera utilizes, in combination with a permanent magnet, anelectromagnet controlled by a F i A li i p i i D pulse-like electricinput to electromagnetically release Oct. 23 1970 Japan /93807 a MableShutter blade from its Stop Fmsitio" to a position for exposing a film.The polarity of the [52] US C 352/169 /53 E 95/53 EA, electric input tothe electromagnet may be reversed so 352/174 as to cause an interactionbetween the electromagnet [51] Int. Cl. G03b 17/46 and the permanentmagnet and the resulting relatwe 58 Field of Search 95/53 E, 53 EA;mvemem the magnets is deteFted and 352/169 174 stop a shutter shaftdrive motor. During a continuous shot, the drive motor may be maintainedoperative [56] References Cited with the aid of the permanent magnetalone and with- UNITED STATES PATENTS out any electric input applied tothe electromagnet.

3,635,141 l/l972 Starp 95/53 EA 14 Claims, 21 Drawing Figures PATENTEU91974 3.784.291 SHEEI' S0? 6 PATENTEU 8'974 SHEEI 6 OF 6 FIG. ll

1 ELECTROMAGNETIC SHUTTER RELEASING DEVICE FOR A PI-IOTOGRAPI-IIC CAMERABACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to an electromagnetic shutter releasing device for aphotographic camera, and more particularly to such a device providedwith electromagnet means and permanent magnet means'to operate means fordriving a shutter blade which controls an exposure.

2. Description of the Prior Art In a still or motion picture camera, itis the usual practice to accomplish a continuous shot by continuouslydepressing a shutter release button and to accomplish a single-frameshot by temporally depressing the shutter button through the use of asimple change-over mechanism. In either case, any incorrect start orstop position of the shutter drive motor would cause the shutter to stopat a position for leaving the film aperture uncovered or cause electriccurrent to flow continuedly even after the motor has stopped. To obviatesuch inconveniences, the following actions must take place in a propersequence:

1. A shutter release switch is closed.

2. A stopper engaged with the drive motor shaft is disengaged therefrom.

3. The motor starts rotating upon closing of the motor circuit.

4. The stopper is maintained in its disengaged position and the motorcontinues to rotate with the motor circuit maintained in its closedcondition.

5. The motor circuit continues its closed condition and the stopperreturns to its initial position.

6. The shutter drive shaft stops at its normal stop position uponengagement of the stopper with a recessed or projected portion formed ina shaft driven by the motor.

To enable this, numerous electromagnetic shutter releasing devices haveheretofore been proposed, but any of these devices when applied to stillor motion picture cameras has encountered a great barrier in that duringthe time when the action under item (4) above occurs, i.e. during acycle of continuous shot when the stopper is maintained out ofengagement with the drive motor shaft, an electric current must continueflowing in the electromagnet to maintain the stopper in such disengagedposition, although this means a substantially high consumption ofelectric power in a motion picture camera whose power source is verymuch limited in capacity. For example, German Patent No. 1,918,733discloses an electromagnetic shutter releasing device'of the type whichutilizes an electromagnet to control a reversible motor and in which acurrent continues to flow through the electromagnet during a continuousshot. Also, German Patent No. 1,948,674 discloses, as an electromagneticshutter releasing device of similar type, a mechanism which employs twoelectromagnets so that a current of relatively great magnitude flows inthe coil on one of the two electromagnets to disengage the stopper fromthe shutter blade drive motor shaft while a current of small magnitudeflows in the coil on the other electromagnet during a continuous shot tomaintain the stopper in its disengaged position. However, even a smallcurrent may result in an increased power comsumption as the number ofthe continuous shots increases, and this mechanism has again encounteredinconveniences when the still or motion picture camera provided withsuch mechanism is used in outdoor environments where the camera mustresort to a power source of limited capacity such as storage battery orthe like.

SUMMARY THE INVENTION It is an object of the present invention toprovide, in a still or motion picture camera, an electromagnetic shutterreleasing device which includes electromagnet means formed of a softmagnetic material having a coil wound thereon and permanent magnet meansinteracting with the magnetic circuit of the electromagnet means and inwhich a stopper for controlling the position of a. rotatable shuttershaft is maintained in released position by the action of the permanentmagnet means during a continuous shot without any electric input appliedto the electromagnet means.

It is another object of the present invention to provide, in a still ormotion picture camera, an electromagnetic shutter releasing device inwhich electric pulses of opposite polarities such as electric currentsare alternately applied to the electromagnet means and the relativemovement of the electromagnet means and the permanent magnet meanscaused by mutual attraction or repulsion therebetween is detected toactuate switching means for controlling the opening and closing of ashutter shaft drive motor circuit so as to enable single-frame shots andcontinuous shots.

It is still another object of the present invention to provide, in astill or motion picture camera, an electromagnetic shutter releasingdevice which further includes operating means movable from a firstposition to a second position or vice versa to change over the motorcircuit switching means so that the switching means is closed for one ofsaid positions and opened for the other positions by the interactionbetween the electromagnet and permanent magnet means, thereby enablingsingle-frame shots and continuous shots.

It is yet another object of the present invention to provide, in a stillor motion picture camera, an electromagnetic shutter releasing devicewhich further includes switch means adapted to close when the shutterblade is not covering the aperture and to open when the shutter blade isin its normal stop position, and in which the switch means, when opened,has one end thereof connected so as to short-circuit the shutter drivemotor circuit to control the stop position of the shutter blade.

It is still another object of the present invention to provide, in astill or motion picture camera, an electromagnetic shutter releasingdevice which further includes means for changing over the direction ofrotation of the shutter shaft drive motor so as to release the stoppermember from its engagement with a shaft driven by the motor irrespectiveof the direction of rotation of the motor.

It is another object of the present invention to provide, in a still ormotion picture camera, an electromag netic shutter releasing devicewhich further includes a capacitor serially connected with a powersource and the electromagnet means and charged or discharged in responseto the change-over of the switch means for opening and closing theshutter drive motor.

Other objects and features of the present invention will become fullyapparent from the following description of embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram forillustrating the principle of the present invention.

FIGS. 2 to 4 show an embodiment of the electromagnetic shutter releasingdevice according to the present invention.

FIGS. 2a, 2b and 2c are a circuit diagram, a front view and a partialside view of the essential portion in this embodiment, and showing aposition ready for photographing with the main switch closed. 7

FIGS. 3a, 3b and 3c are similar to FIGS. 2a, 2b and 20 respectively, butshowing a position where the release switch has been closed to releasethe stopper from its engaging member and start to rotate the drivemotor.

FIGS. 4a, 4b and 4c are also similar to FIGS. 2a, 2b and 2crespectively, but showing a position where the release switch has beenopened.

FIG. 5 is a graph illustrating the actions of various parts of thedevice with the abscissa representing time and the ordinate representingthe angle of rotation of the shutter shaft.

FIGS. 6 and 7 show another embodiment of the device according to thepresent invention.

FIG. 6a is a front view of the essential portion of the device when thestopper is in engagement with the cam.

FIG. 6b is a sectional view taken along line B-B of FIG. 6a.

FIG. 7a is a longitudinal sectional view of the essential portion whenthe stopper is out of engagement with the cam.

FIG. 7b is a sectional view taken along line 8-8 of FIG. 7a.

FIG. 8a is a longitudinal section showing a modified form of the deviceaccording to the present invention.

FIG. 8b is a sectional view taken along line B-B of FIG. 8a.

FIG. 9 shows an example of the electric circuit in the electromagneticshutter releasing device shown in FIGS. 6-8.

FIG. 10 shows another example of the electric circuit.

FIG. 11 shows still another example of the electric circuit.

FIG. 12 is a partly broken-away perspective view showing an entiremotion picture camera which incorporates the electromagnetic shutterreleasing device, especially of the type as shown in FIGS. 6-8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 12 of thedrawings and described in detail hereunder, it is to'be understood thatthe present invention is described with respect to a motion picturecamera of the conventional type having a shutter blade adapted, whenrotated by a camera drive motor, to intermittently uncover an aperturethrough which light may pass for exposing the film thereto.

With this understanding, reference is first had to FIG. 1 to describethe basic construction and operation which is common to the variousembodiments of the present invention to be described hereinafter. Arelease button R may be depressed as indicated by arrow, to close theshown electric circuit. The circuit includes a power source 1, anelectromagnet E of soft magnetic material having a coil We woundthereon, and a control circuit C for controlling the current flowing tothe coil We. The control circuit C includes switching means which may bechanged over to change the direction of the current flowing to the coilWc. A permanent magnet P is disposed so as to interact with the fluxfrom the electromagnet E. Assume that current is being controlled toflow to the coil We in the direction as indicated by arrow. Then theelectromagnet E will have its opposite ends magnetized as poles N and S.Thus, as shown, mutual repulsion will occur between the pole N of thepermanent magnet P and the pole N of the electromagnet E and mutualattraction will occur between the pole N of the magnet P and the pole Sof the electromagnet E. As the result, movable one of the two magnets Eand P will be moved. Operating means D will detect such movement tothereby close or open a motor circuit for driving the shutter shaft ofthe motion picture camera. In FIG. 1, the chain line and the dotted lineboth directed to the operating means D indicate from which of the twomagnets the movement is transmitted. If the current is flowed in thedirection opposite to the direction of the arrow, the movable one of themagnets will be moved also in the opposite direction to allowchange-over of the operating means D. Especially, when the electromagnetE is provided with ferromagnetic members which are magnetizable with theelectromagnet, a durable attraction can occur between the ferromagneticmembers and the electromagnet whether the current to the coil We isinterrupted, and this will lead to a higher efficiency. Furthermore, theoperating means D may be operated simply by applying alternatingelectric pulses to the coil Wc.

Reference is now made to FIGS. 2 through 5 to describe the constructionand operation of an embodiment in which the movable one of the describedtwo magnets is the permanent magnet.

In FIG. 2a, the circuit includes a power source 1, a main power switch2, a capacitor 3, an electromagnet 4, and release switches 5, 6 and 7.The release switches are such that when the switches 5 and 6 assumeposition a the other switch 7 is closed and when the switches 5 and 6assume positions b the switch 7 is open. Parallel-connected with therelease switch 7 is a change-over switch 8 adapted to close during asingleframe shot and to open during a continuous shot. A switch 9 foropening and closing the circuit of motor 10 is connected between thepower source 1 and the motor 10 and actuated by the electromagnet 4. Asshown more particularly in FIGS.'2b and 2c, the switch 9 has its movablecontact selectively engaged with fixed contact 9a or 917 by a rockablemember 12 which is rockable in counterclockwise direction while keepingresilient contact with permanent magnet 11 by means of unshown spring,the permanent magnet l 1 being pivotally movable in the space providedin the magnetic path of the electromagnet 4. One end 1 lb of thepermanent magnet 11 which is remote from the electromagnet 4 is providedwith a stopper 110, which is cooperable with a stopper retaining member13 to limit the pivotal movement of the permanent magnet 11. Therockable member 12 has one end 12b engageable with a cam 14. The stopperretaining member 13 and the cam 14 are both mounted on a shaft 15 whichis driven to rotate at the same angular speed as the shutter shaft (notshown in FIGS. 2b and 2c) by the shutter shaft drive motor 10. In thenormal stop position of the shutter shaft, i.e. in the position as shownin FIGS. 2b and 2c, the stopper 11c is in engagement with a projection13a formed in a circumferential portion of the stopper retaining member13 while the end 12b of the rockable member 12 is in engagement with arecessed portion 14a formed in the cam 14. The rockable member 12 isnormally biased counter-clockwise, as viewed in FIG. 2b, by unshownspring, and one end 12a thereof bears against the adjacent side wall ofthe permanent magnet 11 to limit the counter-clockwise movement of therockable member 12. The change-over switch 9 is such that its movablecontact is engaged with its fixed contact 9a when the end 12b of therockable member 12 is in engagement with the recessed portion 14a of thecam 14 and that its movable contact is engaged with its fixed contact 9bwhen the end 12b of the rockable member 12 is in engagement with thecircular pe ripheral portion 14b of the cam 14.

The operation of the various parts will now be described in particularwith reference to FIGS. 2-4 and FIG. 5.

During a single-frame shot, the change-over switch 8 is in its ONposition (see FIGS. 2a and 3a). When the main switch 2 is closed, thecapacitor 3 is charged by the power source 1 since the movable contactsof the release switches 5 and 6 are then engaged with the fixed contactsa as shown in FIG. 2a. By that time, the shutter shaft has already beenstopped at its normal stop position upon completion of the precedingshot, and as seen in FIG. 2b, the end 11a of the permanent magnet 11 hasbeen attracted to the end face 4a of the electromagnet 4 while thestopper 11c is in engagement with the end 13a of the retaining member 13and the end 12b of the rockable member 12 is in engagement with therecessed portion 14a of the cam 14. Therefore, the movable contact ofthe switch 9 is engaged with the fixed contact 9a and not with the fixedcontact 9b. Subsequently, the shutter release button is drpressed tochange over the release switches 5 and 6 from their contacts a to theircontacts b and change over the switch 7 from its ON position to its OFFposition (the position at t= in FIG. Thus, the charge stored in thecapacitor 3 is discharged to the coil on the electromagnet 4 so that acurrent flows in the direction as indicated by the solid-line arrow inFIG. 3a, whereby the electromagnet 4 is polarized as shown in FIG. 3b.Therefore, if the permanent magnet 11 is magnetized with its end 11a asN pole and its end 11b as S pole, the end 1 la of the magnet 11 and theend 4a of the electromagnet 4 will repulse each other while the ends 11aand 4b will attract each other, whereby the permanent magnet 11 willpivot from the position of FIG. 2b to the position of FIG. 3b until itsend 11a is stopped by the end 4b of the electromagnet 4 (t='r Prior tothis, during the pivotal movement of the magnet 11, the stopper 11c hasalready been disengaged from the projection 13a of the retaining member13 (F13), whereafter the movable contact of the switch 9 is engaged withthe fixed contact 9b by means of the rockable member 12 (P7 so that theshutter shaft drive motor circuit is closed to cause the shutter bladeto begin rotating (0=0) and at the same time the shaft begins rotatingat a speed ratio of l l with respect to the shutter shaft, whereupon theretaining member 13 and cam 14 also begin to rotate with the shaft 15.The discharging capacity of the capacitor is preset such that thedischarging time is i=0 r Since the cam 14 begins to rotate in thedirection of arrow in FIG. 3c as soon as the motor l0 begins rotating,the end 12b of the rockable member 12 rides on the circular peripheralportion 14b of the cam 14 to maintain the movable contact of the switch9 in engagement with the fixed contact 9b until the end 12b reaches therecessed portion 14a of the cam 14, thereby allowing the motor 10 tocontinue its rotation and accordingly allowing the shutter shaft tocontinue its rotation at a predetermined speed from 0=0 in FIG. 5.

On the other hand, independently of the discharge circuit of thecapacitor 3, a current flows in the direction as indicated by imaginaryarrow in FIG. 3a, after the point of time t=r because of the movablecontact of the switch 9 engaged with the fixed contact 9b. At the pointof time 1 almost all of the charge in the capacitor 3 has beendischarged to leave only a very small quantity of current flowing in thedirection of solid-line arrow. Therefore, the polarity of theelectromagnet 4 is changed as shown in FIG. 4b and the permanent magnet11 is allowed to return to its position of FIG. 4b, i.e. the positionwhere the stopper is engaged with the projection 13a of the retainingmember 13. By that time, however, the end 12b of the rockable member 12has ridden on the circular peripheral portion 14b of the cam 14 torestrict the counter-clockwise rotation of the rockable member, and thusthis rockable member maintains the movable contact of the switch 9 inengagement with the fixed contact 9b until the end 12b reaches theterminus of the circular peripheral portion 14b of the cam 14.Accordingly, the rotation of the motor 10 continues until the end 12b ofthe rockable member 12 comes into the recessed portion 14a of the cam 14to change over the movable contact of the switch 9 into engagement withthe fixed contact 9a. When the end 12b has come into the recessedportion (Faat which the shutter shaft has been rotated to an angle 0,),the aforesaid change-over of the switch 9 not only closes the circuit ofthe motor 10 but also forms a short circuit as shown in FIG. 2a, wherebythe rotational energy of the motor is well consumed to pro vide a verygood brake and minimize the shock between the stopper llc and theretaining portion 13a of the retaining member 13, as compared with thecase where no short circuit is formed in the motor 10.

It will thus be appreciated that a single depression of the releasebutton enables not only a single-frame shot to take place but also theshutter shaft to stop at its normal position (t=T 0=21r).

To accomplish a continuous shot, the change-over switch 8 is brought toits OFF position in FIG. 2a. The release button is depressed to changeover the release switches from their contacts a to their contacts b andthe switch 7 is closed (t==0), so that the electromagnet 4 is magnetizedby the discharge current from the capacitor 3 to pivotally move thepermanent magnet 11, as shown in FIG. 3b, whereafter the stopper 11c isdisengaged from the retaining member 13 (P03) and then the movablecontact of the switch 9 engages the fixed contact 9b to close the motorcircuit (t= r From then till the point of time t='r the same operationoccurs as that described above with respect to the single-frame shot.That is, the capacitor 3 discharges to pass a cur rent to theelectromagnet 4 in the direction of solid-line arrow in FIG. 3a untilthe point of time F4, is reached. In this case, however, the switch 8 isopen and therefore, no current flows in the direction of the imaginaryarrow, despite the engagement between the movable contact and fixedcontact 9b of the switch 9 resulting from the permanent magnet l 1attracted to the electromagnet 4. Thus, the stopper 11c is maintained inthe position as shown in FIG. 3a, whereby the motor is allowed tocontinue its rotation to continuously drive the shutter blade for acontinuous shot.

To terminate the shot, the release button is released from its depressedposition to change over the release switches 5 and 6 from their contactsb to their contacts a and close the switch 7 (t='r 6=0,,). Thereupon, acurrent flows in the direction indicated by the imaginary arrow in FIG.4a to cause mutual attraction between the end 4a of the electromagnet 4and the end 11a of the permanent magnet 11 and mutual repulsion betweenthe end 4b of the electromagnet and the said end 11a of the permanentmagnet, whereby the permanent magnet 11 is attracted into engagementwith the end 4a of the electromagnet to return the stopper 11c intoengagement with the projection 13a of the retaining member 13 (t= r,).Nevertheless, the drive motor maintains its rotation because the switch9 maintains its movable contact in engagement with its fixed contact 9bas long as the end 12b of the rockable member 12 is engaged with thecircular peripheral portion 14b of the cam 14. Thereafter, the end 12bof the rockable member 12 comes into the recessed portion 14a of the cam14 (t='r (i=0 so that the movable contact of the switch 9 shifts fromthe contact 9b to the contact 9a to open the motor circuit and form ashort circuit in the same way as described previously with respect tothe single-frame shot. Thus, the shaft 15 now rotates due to its inertiato bring the projection 13a of the retaining member 13 thereon intoengagement with the stopper 11c until the shutter shaft associated withthe rotary shaft 15 is stopped at its normal stop position.

FIGS. 6 to 11 show further embodiments of the electromagnetic shutterreleasing device according to the present invention, wherein use is madeof a stationary permanent magnet, a stationary electromagnet, movableferromagnetic members magnetized by the stationary electromagnet andco-acting with the electromagnet, and a switch changed over to open andclose the shutter shaft drive motor upon detection of the movement ofthe ferromagnetic members.

In FIGS. 6a and 7a, a permanent magnet 21 is attached to a first yoke 22and an electromagnet coil 23 is mounted on a second yoke 24. Thepermanent magnet 21 and the second yoke 24 are closely joined togetherto provide a magnetic path. A slidable rod 25 is slidably supported bythe first and second yokes 22 and 24 and also acts as the core for theelectromagnet 23. The slidable rod 25 has a pair of ferromagneticmembers 26, 27 secured thereto and interposed between the two yokes 22and 24. A stopper 28, which includes a ramp portion 28a, a steppedportion 28b and an end face 280, is provided at one end of the slidablerod 25. A switch 29 is provided to open and close a motor circuit fordriving the unshown shutter shaft of a motion picture camera. A rotaryshaft 30 is associated with the unshown shutter shaft for rotationtherewith at a speed ratio of l l. The shaft 30 carries thereon a cam 31including a recessed portion 310, a circular peripheral portion 31b andan end face 31c. The electromagnetic releasing device thus constructedmay be mounted to a motion picture camera body by means of a plate 36.

FIG. 6 shows a position in which the stopper 28 is engaged with the can31 to open the switch 29 with no current flowing to the electromagnet 23while the ferromagnetic members 26, 27 are attracted into engagementwith the first and second yokes 22, 24 respectively to lock the shaft30. This position is the stop position of the shutter shaft and blade.In such position, if a current is flowed to the electromagnetic coil 23in a direction for magnetizing the ferromagnetic members 26, 27 as polesN and S respectively, then mutual repulsion will occur between theferromagnetic member 26 and the first yoke 22 and between theferromagnetic member 27 and the second yoke 24, respectively, wherebythe slidable rod 25 will be displaced in a direction for closing theswitch 29 and will thus close this switch when the stepped portion 28bof the stopper has been disengaged from the end face 310 of the cam 31but the ramp portion 28a of the stopper 28 will still be in engagementwith the cam end face 310. Thus, the motor (not shown) will be energizedto drive the cam shaft 30 for rotation.

On the other hand, the slidable rod 25 will further move until theferromagnetic members 26, 27 are attracted into engagement with theyokes 24, 22, thus attaining the position as shown in FIG. 7. Even ifthe current to the electromagnet coil 23 is then cut off, the slidablerod 25 will be maintained in its position of FIG. 7 by the attractionacting between the ferromagnetic members 26, 27 and the yokes 24, 22.

When a current is flowed to the electromagnetic coil 23 in the oppositedirection, the ferromagnetic members 26 and 27 will be magnetized withopposite polarities to those shown in FIG. 6, so that mutual repulsionwill occur between the ferromagnetic members 26, 27 and the yokes 24, 22to cause the slidable rod 25 to move in the direction for opening theswitch 29. By that time, however, the circular peripheral portion 31b ofthe cam 31 has usually become ready for engagement with the stopper 28and therefore, the left end face 280 of the stopper 28 will first engagethe right end face 310 of the cam 31 even if the stopper is moved backor leftwardly as viewed in the figure. In this position, the switch 29has not been opened yet. When the cam 31 is rotated in the direction asindicated by arrow in FIG. 6b to bring its recessed portion 31a into aposition for engagement with the stopper 28, the stopper 28 which ischamfered at the portion defining the end face 280 will further moveback or leftwardly until its ramp 28a is engaged with the recessedportion 31a of the cam 31, whereupon the switch 29 will be opened toform an open motor circuit, thereby electrically deenergizing the motor.Nevertheless, the motor will continue its rotation due to its inertiauntil the stepped portion 28b of the stopper 28 is engaged with therecessed portion 31a of the cam 31 to stop the rotation of the cam shaft30, thus restoring the position as shown in FIG. 6.

A single-frame shot may be achieved when the above-described operationsare carried out in a sequence. Also, a continuous shot may be achievedwhen a current continues flowing through the motor circuit while thestopper is maintained out of engagement with the cam 31. In the lattercase, as in the case of a singleframe shot, the termination of the shotmay be accomplished by passing a current of the opposite polarity to theelectromagnet coil 23 to stop the shutter shaft at its normal stopposition.

During such operation, the attraction of the permanent magnet 21 maytend to cause so intimate contact between the ferromagnetic members 26,27 and the yokes 22, 24 that it will be difficult to release suchcontact with the aid of the electromagnetic force of the electromagnetalone. For this reason, it is desirable to provide springs 32, 33 forimparting resilient forces in such directions as to negate the strongattractions acting between the ferromagnetic members 26, 27 and theyokes 22, 24. Adjust screws 34, 35 may be provided to adjust theresilient forces of such springs 32, 33.

FIGS. 8a and 8b show a further modification of the present invention, inwhich the second yoke 24 comprises a pair of yoke members 24, and 24disposed with their open ends facing each other and a rockable member 38is pivoted at a fulcrum 37 located at the center of the yoke 24 and hasone end portion disposed between the flanges 39 and 39 of a slidable rod25. In FIG. 8, one of such flanges 39 is shown as being provided by thestopper 28.

The rockable member 38 may be rotated about the fulcrum 37 in eitherdirection depending on the direction of the current flowing to theelectromagnet coil 23, thereby moving the slidable rod 25 rightwardly orleftwardly, as viewed in FIG. 8a, to control the opening and closing ofthe switch 29 in the same way as described with respect to FIGS. 6 and7. When the rockable member 38 is rotated until its opposite ends areattracted into engagement with the opening edges of the yoke members 24and 24 the rockable member 38 retains the slidable rod. Thus, thearrangement of FIG. 8 eliminates the need to provide the ferromagneticmembers 26, 27 as shown in the embodiment of FIGS. 6 and 7. The stopper28 and the cam 31 as well as the entire device are the same in operationas those described previously, and these need not be described further.

In the embodiment described so far, the shaft 30 may be arranged forrotation in either of the normal and reverse directions. In FIGS. 6 to8, reference numeral 40 designates a gear for connecting the cam shaft30 to the drive motor shaft. In the embodiments of the described type,the permanent magnet is actuated in accordance with the direction of thecurrent flowing to the electromagnet so that the switch for opening andclosing the shutter shaft drive motor circuit is changed over by theslidable rod moving between its first and second positions, whereuponthe slidable rod is attracted and retained at either of these positions(i.e. the stop end positions) by the permanent magnet. Accordingly,current must be flowed to the electromagnet coil only when the slidablerod is to be actuated, and no holding current must be flowed once theslidable rod is actuated. This also holds true with the embodiment ofFIGS. 2-4. In this way, the device according to these embodiments mayminimize the power consumption and is very effective as theelectromagnetic shutter releasing device for opening and closing themotor circuit in a motion picture camera which is compelled to use acompact power source of small capacity.

FIGS. 9 to 11 illustrate some examples of the electric circuit throughwhich currents of opposite polarities may alternately flow to theelectromagnet coil 23.

In the circuit of FIG. 9, a serial connection of electromagnet coil 23,capacitor 41 and release switch 42 is parallel-connected with a powersource 43. When power switch 44 is closed to change over the releaseswitch 42 from its contact a to its contact b, the current charged inthe capacitor 41 will flow to the electromagnet coil 23 to cause theslidable rod 25 to close switch 29 and accordingly close the circuit ofmotor 45. If the release switch 42 is then changed over from its contactb to its contact 2, the charge from the capacitor 41 will flow throughthe electromagnet coil 23 in the opposite direction, thereby moving backthe slidable rod 25 to close the switch 29.

The circuit arrangement shown in FIG. 10 includes an ordinary switch 46adopted as release switch, instead of the change-over switch 42, atransistor 47 parallel-connected with the electromagnet coil 23 andcapacitor 41, a diode 48 inserted between the base and emitter of thetransistor and a resistor 49 inserted between the base and collector ofthe transistor. When the release switch 46 is closed, the capacitor 41will be charged through the electromagnet coil 23 so that the slidablerod 25 will be moved similarly to the case of FIG. 9, thereby closingthe switch 29. When the release switch 46 is opened, the transistor 47will be rendered conductive by the charge current from the capacitor 41,which will thus discharge through the circuit 41-2- 3-47-41. Thereupon,the attraction of the electromagnet will act to move the slidable rod 25so as to open the switch 29 and accordingly open the motor circuit.

In FIGS. 9 and 10, a coil 50 wound with the opposite polarity to that ofthe coil 23 is provided to effect a single-frame shot. Preferably, thecoil 50 is wound at the same location as the coil 23. If switch 51 forswitching the mode of photographing between the single-frame shot andthe continuous shot is closed to bring the movable contact of therelease switch 42 into engagement with the fixed contact b (or, in FIG.10, to close the release switch 46), a current will flow in the coil 23so that interaction between the electromagnet and the permanent magnetwill cause the slidable rod 25 to be mechanically moved and therebyclose the switch 29. As the result, a current will also flow in themotor 45 and coil 50. The length of time during which the currentcontinues flowing in the coil 23 is limited to the charging time of thecapacitor 41, but the slidable rod 25 for holding the switch 29 in itsON position may be maintained in its operative position by theattraction acting between the ferromagnetic member or the ferromagneticrockable member and the permanent magnet. However, since the closedswitch 29 causes a current of the opposite polarity to begin flowing inthe coil 50 and coil 23, the electromagnet will be oppositely polarizedif the current of the opposite polarity increases its quantity, wherebythe movable ferromagnetic member tends to restore its initial positionand actuate the slidable rod 25 so as to bring the stopper 28 integraltherewith into engagement with the cam 31. Thus, the closed switch 29will now be opened to deenergize the motor and stop the shutter shaft atits predetermined position. This completes one cycle of single-frameshot.

FIG. 11 shows another example of the circuit arrangement in which coils23 and 50 pass a current therethrough only in one direction. When theswitch 52 is open, a single-frame shot can be effected in the manner tobe described, in accordance with the abovedescribed principle. If therelease switch 46 is closed, base current of transistor 57 will flow andcurrent will thus flow to the coil 23 until capacitor 56 is charged,whereupon the engagement between the stopper 28 and the cam 31 ismechanically released to allow the slidable rod 25 to move and close theswitch 29, thereby admitting a current into the motor 45. At the sametime, capacitor 60 begins to be charged through l 1 resistor 58 and whenthis charging is finished, base and collector currents of anothertransistor 59 begin to flow and thus, a current of the opposite polarityto that of the current flowing in the coil 23 will flow in the coil 50.As the result, the slidable rod 25 will move back to its initialposition in the described manner, thereby mechanically engaging thestopper 28 with the cam 31 and opening the switch 29 to deenergize theshutter shaft drive motor 45.

If the switch 52 is then closed, a continuous shot will be enabled totake place in the manner described hereunder. After the release switch46 is closed and until the switch 29 is closed to energize the motor 45,the operation will occur in the same way as described above with respectto the single-frame shot. Thereafter, the release switch 46 ismaintained in its closed position to allow all the current flowing inthe resistor 58 to pass through the switch 52 and release switch 46, andthus the capacitor 60 will not be charged despite the closed position ofthe switch 29. Accordingly, the base potential of the transistor 59 willbe zero volt and this transistor will not conduct any current to thecoil 50. In this way, a continuous shot will continue with the releaseswitch 46 maintained in its ON position. When the release switch 46 isopened, the capacitor 60 will be charged through the resistor 58 to turnon the transistor 59, which thus conducts a current to the coil 50.Accordingly, the slidable rod 25 will be moved back to open the switch29 to deenergize the shutter shaft drive motor 45 while bringing thestopper 28 integral with the slidable rod 25 into mechanical engagementwith the cam 31 integral with the cam shaft connected to the shuttershaft. Thus, the shutter shaft is stopped at its predetermined stopposition, whereupon the continuous shot is terminated. Resistors 53 and54 are those through which the capacitor 56 may discharge, and switches61 and 62 are transfer switches for changing over the rotation of themotor 45 between the normal and reverse directions.

FIG. 12 illustrates a conventional motion picture camera body 100 whichincorporates therein the described electromagnetic shutter releasingdevice of the present invention. The permanent magnet is designated by21, and the electromagnet is comprised of coils 23 and 50 of theopposite polarities. Stopper 28, cam shaft 30, cam 3], gears 40 anddrive motor 45 are the same as those shown and described above. An idler70 is provided to transmit the rotation of the motor 45 to the shuttershaft 71, which has a shutter blade 72 securely mounted thereon. Theidler 70 and the shutter blade 72 are rotatable in the directions asindicated by respective arrows when a gear 73 on the motor shaft isdirven to rotate in the direction of arrow. A magazine 74 containstherein a roll of film 75. The shutter blade 72, when rotated, controlsthe time during which the film is exposed through a film aperture 76.Light enters through a zoom lens 77 in the direction as indicated by achain-line arrow and is partly directed through a relay lens 78 to thefilm aperture 76 and partly directed upwardly and the horizontally to aviewfinder. A worm gear 79 is provided to transmit the rotation of thecam shaft via worm wheel 80 to a film take-up gear 81. The take-up gear81 may be rotated in the direction of arrow to take up the film when themotor 45 is rotating in the direction of arrow. Numeral 82 designates ashutter release button which may be depressed to actuate the releaseswitch (not shown in FIG. 12).

The present invention, as described above, utilizes the charging anddischarging currents of a capacitor to alternately flow. a currentthrough an electromagnet coil in opposite directions and this onlyrequires a very simple circuit arrangement to achieve the intendedpurposes. Furthermore, the charging and discharging currents of thecapacitor flow so abruptly at the intial stage of the charging and thedischarging cycle as to ensure positive energization of theelectromagnet and positive attraction or repulsion between theelectromagnet and the permanent magnet or the ferromagnetic members,thereby enabling the shutter shaft drive motor to start and stopaccurately. Moreover, switch means may be operated to allow the drivemotor to continue its rotation with the aid of the permanent magnetalone but without any current flowing to the electromagnet, and thusboth a single-frame shot and a continuous shot may be accomplished witha'minimum power consumption in the motion picture camera.

We claim:

1. In an electromagnetic shutter release control device for use with amotion picture camera, a combination comprising:

shutter means rotatable from a predetermined position for exposing afilm;

driving means for rotatably driving said shutter means;

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

release switch means movable between an OFF position and an ON positionfor operating the camera; switching means arranged between said drivingmeans and said power supplying means for connecting and disconnectingsaid driving means with said power supplying means to permit theselective supply of electric energy to said driving means; a movablemember operatively engageable with said switching means for actuatingsaid driving means;

actuating means for actuating said movable member to activate saidswitching means, said actuating means including permanent magnet means,a pair of coils wound around a soft magnetic material and electromagnetmeans, and said electromagnet means, when energized by said powersupplying means, actuating said movable member by interaction betweenthe electromagnetic field produced by said electromagnet means and themagnetic field by said permanent magnet means;

blocking means actuatable by said actuating means and engageable with atleast a portion of said shutter means to fix the shutter means at apredetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; and

power supply control circuit means including a first circuit which whenthe camera is continuously shooting, provides, in response to theturning of said release switch from OFF position to ON position, theelectric current supply to the first coil of said electromagnet during apredetermined time from the turning operation, and a second circuitwhich provides, in response to the turning of said release switch fromON position to OFF position, the electric current supply to the secondcoil of said electromagnet during a predetermined time from the turningfrom ON position to OFF position, thereby disconnecting the power supplyfrom said power supplying means to said actuating means duringcontinuous shooting; 1

said blocking means being moved, when continuously shooting, into saidsecond rest position thereof by the movement of said movable member, andbeing maintained at said second rest position even after the electricpower supply from said power supplying means is stopped by said controlcircuit means, thereby permitting the continuous operation of saidshutter means.

2. A combination as defined in claim 1, wherein said movable membermaintains said switch means in said connecting condition when saidshutter means is not positioned at said predetermined position thereof.

3. In a photographic camera capable of continuous shooting, acombination comprising:

shutter means rotatable from a predetermined position for exposing afilm;

said shutter means including a rotatable shutter blade and a shuttershaft for rotatably supporting said blade thereon,

driving means for rotatably driving said shutter means,

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

switching means arranged between said driving means and said powersupplying means, said switching means connecting and disconnecting saiddriving means with said power supplying means to permit the selectivesupply of electric energy to said driving means;

actuating means for actuating said driving means through said switchingmeans, said actuating means including permanent magnet means,electromagnetic means and control means for controlling the electricenergy supply to the electromagnetic means;

and blocking means actuatable by said actuating means and engageablewith at least a portion of said shutter means to fix the shutter meansat a predetermined position thereof, and having a first rest positionfor stopping the movement of said shutter means and a second restposition for releasing the movement of the shutter means;

said blocking means being moved, when continuous shooting, into saidsecond rest position thereof, and being maintained at said second restposition even after the electric energy supply from said power supplyingmeans is stopped by said control means, thereby permitting thecontinuous operation of said shutter means.

4. In a photographic camera capable of continuous shooting, acombination comprising:

shutter means rotatable from a predetermined position for exposing afilm;

driving means for rotatably driving said shutter means,

said driving means including a reversible drive motor and a member fortransmitting the drive of said motor to said shutter means,

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

switching means arranged between said driving means and said powersupplying means, said switching means connecting and disconnecting saiddriving means with said power supplying means to permit the selectivesupply of electric energy to said driving means;

actuating means for actuating said driving means through said switchingmeans, said actuating means including permanent magnet means,electromagnetic means and control means for controlling the electricenergy supply to the electromagnetic means;

and blocking means actuatable by said actuating means and engageablewith at least a portion of said shutter means to fix the shutter meansata predetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; i

said blocking means being moved, when continuous shooting, into saidsecond rest position thereof, and being maintained at said second restposition even after the electric energy supply from said power supplyingmeans is stopped by said control means, thereby permitting thecontinuous operation of said shutter means.

5. In a photographic camera capable of continuous shooting, acombination comprising:

shutter means rotatable from a predetermined position for exposing afilm;

driving means for rotatably driving said shutter means,

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

said power supplying means including a storage batswitching meansarranged between said driving means and said power supplying means, saidswitching means connecting and disconnecting said driving means withsaid power supplying means to permit the selective supply of electricenergy to said driving means;

actuating means for actuating said driving means through said switchingmeans, said actuating means including permanent magnet means,electromagnetic means and control means for controlling the electricenergy supply to the electromagnetic means;

and blocking means actuatable by said actuating means and engageablewith at least a portion of said shutter means to fix the shutter meansat a predetermined position thereof, and having a first rest positionfor stopping the movement of said shutter means and a second restposition for releasing the movement of the shutter means;

said blocking means being moved, when continuous shooting, into saidsecond rest position thereof, and being maintained at said second restposition even after the electric energy supply from said power supplyingmeans is stopped by said control means, thereby permitting thecontinuous operation of said shutter means.

6. In an electromagnetic shutter release control device for use with amotion picture camera, a combination comprising:

shutter means rotatable from'a predetermined position for exposing afilm;

driving means for rotatably driving said shutter means;

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

release switch means movable between an OFF position and an ON positionfor turning the camera into operating condition in response to a shutterreleasing operation of said camera;

switching means arranged between said driving means and said powersupplying means for con necting and disconnecting said driving meanswith said power supplying means to permit the selective supply ofelectric energy to said driving means;

a movable member operatively engageable with said switching means foractuating said driving means;

actuating means for actuating said movable member to activate saidswitching means, said actuating means including permanent magnet meansand electromagnet means, and said electromagnet means, when energized bysaid power supplying means, actuating said movable member by interactionbetween the electromagnetic field provided by said electromagnet meansand the magnetic field by said permanent magnet means;

blocking means actuatable by said actuating means and engageable with atleast a portion of said shutter means to fix the shutter means atapredetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; and

an electromagnetical control circuit controlling the direction of thecurrent through said electromagnetic means so that when said blockingmeans is moved from said first rest position thereof to said second restposition thereof, the current flows through said electromagnetic meansin a first direction, and when said blocking means is moved from saidsecond rest position thereof to said first rest position thereof, thecurrent flows through said electromagnetic means in a second directionopposite to said first direction, thereby changing the polarity of themagnetic poles of said electromagnetic means;

said blocking means being moved, when continuously shooting, into secondrest position thereof by the movement of said movable member, and beingmaintained at said second rest position even after the electric powersupply from said power supplying means is stopped by said controlcircuit means, thereby permitting the continuous operation of saidshutter means.

7. A combination as defined in claim 1, wherein said blocking meansincludes a stopper member movable by the interaction of said permanentmagnet means and said electromagnetic means engageable with at least aportion of said shutter means.

8. A combination as defined in claim 1, wherein said shutter meansincludes a cam member engageable with said blocking means for stoppingthe shutter means precisely at said predetermined position. I

9. A combination as defined in claim 6, wherein said electromagneticmeans further comprises two coils wound substantially at the same placefor flowing a respective opposite-directional currenttherethrough tomagnetize said electromagnetic means.

10. In an electromagnetic shutter release control device for use with amotion picture camera, a combination comprising:

shutter means rotatable from apredetermined position for exposing afilm;

driving means for rotatably driving said shutter means;

power supplying means operatively connected to 'said driving means forsupplying electric energy thereto;

switching means arranged between said driving means and said powersupplying means for connecting and disconnecting said driving means withsaid power supply means to permit the selective supply of electricenergy to said driving means; release switch means movable between anOFF position to an ON position for operating the camera; a movablemember operative engageable with said switching means for actuating saiddriving means;

actuating means for actuating said driving means through said switchingmeans, said actuating means including permanent magnet means andelectromagnetic means having a pair of coils wound around a softmagnetic material, and said electromagnet means, when energized by saidpower supplying means, actuating said movable member by interactionbetween electromagnetic field provided by said electromagnet meansandmagnetic field by said permanent magnet means; blocking means actuatableby said actuating means and engageable with at least a portion of saidshutter means to fix the shutter means at a predetermined positionthereof, and having first rest position for stopping the movement ofsaidshutter means and second rest position for releasing the movement ofthe shutter means; and

control circuit means including a first capacitorresistor combination, afirst transistor for adjusting the supplying time of electric current toone of said coils, the input voltage of said first transistor beingcontrolled by said first capacitor-resistor combination, a secondcapacitor-resistor combination and a second transistor for adjusting thesupplying time of the electric current to another one of said coils, theinput voltage of said second transistor being controlled by said secondcapacitor-resistor combination;

said blocking means being moved, when continuous shooting, into saidsecond rest position thereof by energization of said first coil, andbeing maintained at said second rest position even after the electricenergy supply from said power supplying means is stopped by said controlcircuit means, thereby permitting the continuous operation of saidshutter means.

11. In an electromagnetic shutter release control device for use with amotion picture camera, a combination comprising:

shutter means rotatable in either direction from a predeterminedposition for exposing a film; driving means for rotatably driving saidshutter means;

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

switching means arranged between said driving means and said powersupplying means, said switching means connecting and disconnecting saiddriving means with said power supplying means to permit the selectivesupply of electric energy to said driving means;

electromagnet means for selectively actuating said switching means forenergizing said driving means in response to a shutter rlease operationof said camera;

control circuit means for controlling said electromagnet means, saidcontrol circuit means including a pair of capacitor-resistorcombinations, a pair of transistors, the input voltages of saidtransistors being controlled by said capacitor-resistor combinations,respectively, and selector switch means for controlling the introductionof said pairs into said circuit; and

blocking means actuatable by said electromagnet means through saidcontrol circuit means for blocking said shutter means in eitherrotational direction thereof, said blocking means having a first restposition for maintaining said switching means at non-actuated conditionthereof and stopping the rotational movement of said driving means ineither direction, and a second rest position for maintaining saidswitching means at actuated condition thereof and releasing therotational movement of said driving means in either direction, saidblocking means further comprising a movable portion which is movableinto and out of at least a portion of the locus of the rotation of saidshutter means said shutter means having a rotatable portion engageablewith said movable portions, thereby stopping the rotational movement ofsaid shutter means in either direction when said two portions are movedto engage each other.

12. In an electromagnetic shutter release control device for use with amotion picture camera, a combination comprising:

shutter means rotatable from a predetermined position for exposing afilm; driving means for said shutter means;

power supplying means operatively connected to said driving means forsupplying electric energy thereto; switching means arranged between saiddriving means and said power supplying means for connecting anddisconnecting said driving means with said power supplying means topermit the selective supply of electric energy to said driving means;

electromagnetic means for controlling said driving means through saidswitching means;

engaging means rotatable integrally with said shutter means;

blocking means including a first movable member and a second movablemember; and

control circuit means having a timing circuit for controlling theenergization of said electromagnetic means, said control circuit meanspermitting, when said switching means is changed from a first positionthereof to a second position thereof, electric current through saidelectromagnet means in the direction to actuate said first movablemember, and while said second switch is subsequently maintained at saidsecond position thereof, stopping said electric current through saidelectromagnet means after an elapse of time determined by said timingcircuit, and when said switching means is returned from said secondposition to said first position, permitting electric current throughsaid electromagnet means in the direction opposite to said direction.

13. In a motion picture camera, an electromagnetic shutter releasingdevice for electromagnetically releasing a movable shutter from its restposition to expose a film through an aperture and for stopping theshutter at a predetermined position at the end of the exposure, saiddevice comprising:

shutter means;

driving means for said shutter means;

power supplying means operatively connected to said driving means forsupplying electric energy thereto;

switching means arranged between said driving means and said powersupplying means, said switching means connecting and disconnecting saiddriving means with said power supplying means to permit the selectivesupply of electric energy to said driving means;

electromagnetic means connected to said power supplying means throughsaid switching means and magnetizable with opposite polarities inresponse to the changes in the direction of the current through saidelectromagnetic means;

permanent magnet means located adjacent said electromagnetic means tointeract with the electromagnetic means; controlling means forcontrolling the movement of said shutter means, said controlling meanshaving a member movable by the interaction of said electromagnetic meansand permanent magnet means, said movable member being movable between afirst position for stopping the rotational movement of said shuttermeans and a second position for permitting the rotational movement ofsaid shutter means; and said movable member being moved, when continuousshooting, into said second position thereof, and being maintained atsaid second position even after the electric energy supply from saidpower supplying means is stopped, thereby permitting the continuousoperation of said shutter means,

adjusting means operatively connected to said movable member foradjusting the attracting force caused by the interaction of saidelectromagnetic means and said permanent magnet means, said adjustingmeans including an adjustably contacting member to said movable member,and a setting member to adjustably set said contacting member thereby toenable said electromagnet means to move said movable member onlysupplying a small current to the electromagnetic means.

14. In an electromagnetic shutter release device for use with a motionpicture camera being selectively capable of a single frame exposure anda continuous filming, said device having at least one magnetic circuitincluding a permanent magnet and an electromagnet, an improvementcomprising:

permanent magnet means;

electromagnet means interacting with said permanent magnetic means;

power supplying means for actuating said electromagnet means;

movable means driven by the magnetic interaction of said permanentmagnet means and said electro- I magnet means,;

shutter release means movable between a first position for releasing theshutter and a second position said shutter,

switch means actuatable by said movable means when the latter ispositioned at its extreme position; and

adjusting means for reducing the interaction forces of for stopping theshutter;

said movable means having a first position for mainsaid electromagnetmeans and said permanent magnet means, said adjusting means includingtwo independently operable adjusting members, one of which operates toreduce the attractive force between said two magnet means in a directionin which said switch means is actuated and the other of which operatesto reduce the attractive force in the opposite direction thereby toenable to move said movable means with a small current supplied to saidelectromagnet.

1. In an electromagnetic shutter release control device for use with amotion picture camera, a combination comprising: shutter means rotatablefrom a predetermined position for exposing a film; driving means forrotatably driving said shutter means; power supplying means operativelyconnected to said driving means for supplying electric energy thereto;release switch means movable between an OFF position and an ON positionfor operating the camera; switching means arranged between said drivingmeans and said power supplying means for connecting and disconnectingsaid driving means with said power supplying means to permit theselective supply of electric energy to said driving means; a movablemember operatively engageable with said switching means for actuatingsaid driving means; actuating means for actuating said movable member toactivate said switching means, said actuating means including permanentmagnet means, a pair of coils wound around a soft magnetic material andelectromagnet means, and said electromagnet means, when energized bysaid power supplying means, actuating said movable member by interactionbetween the electromagnetic field produced by said electromagnet meansand the magnetic field by said permanent magnet means; blocking meansactuatable by said actuating means and engageable with at least aportion of said shutter means to fix the shutter means at apredetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; and power supplycontrol circuit means including a first circuit which when the camera iscontinuously shooting, provides, in response to the turning of saidrelease switch from OFF position to ON position, the electric currentsupply to the first coil of said electromagnet during a predeterminedtime from the turning operation, and a second circuit which provides, inresponse to the turning of said release switch from ON position to OFFposition, the electric current supply to the second coil of saidelectromagnet during a prEdetermined time from the turning from ONposition to OFF position, thereby disconnecting the power supply fromsaid power supplying means to said actuating means during continuousshooting; said blocking means being moved, when continuously shooting,into said second rest position thereof by the movement of said movablemember, and being maintained at said second rest position even after theelectric power supply from said power supplying means is stopped by saidcontrol circuit means, thereby permitting the continuous operation ofsaid shutter means.
 2. A combination as defined in claim 1, wherein saidmovable member maintains said switch means in said connecting conditionwhen said shutter means is not positioned at said predetermined positionthereof.
 3. In a photographic camera capable of continuous shooting, acombination comprising: shutter means rotatable from a predeterminedposition for exposing a film; said shutter means including a rotatableshutter blade and a shutter shaft for rotatably supporting said bladethereon, driving means for rotatably driving said shutter means, powersupplying means operatively connected to said driving means forsupplying electric energy thereto; switching means arranged between saiddriving means and said power supplying means, said switching meansconnecting and disconnecting said driving means with said powersupplying means to permit the selective supply of electric energy tosaid driving means; actuating means for actuating said driving meansthrough said switching means, said actuating means including permanentmagnet means, electromagnetic means and control means for controllingthe electric energy supply to the electromagnetic means; and blockingmeans actuatable by said actuating means and engageable with at least aportion of said shutter means to fix the shutter means at apredetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; said blocking meansbeing moved, when continuous shooting, into said second rest positionthereof, and being maintained at said second rest position even afterthe electric energy supply from said power supplying means is stopped bysaid control means, thereby permitting the continuous operation of saidshutter means.
 4. In a photographic camera capable of continuousshooting, a combination comprising: shutter means rotatable from apredetermined position for exposing a film; driving means for rotatablydriving said shutter means, said driving means including a reversibledrive motor and a member for transmitting the drive of said motor tosaid shutter means, power supplying means operatively connected to saiddriving means for supplying electric energy thereto; switching meansarranged between said driving means and said power supplying means, saidswitching means connecting and disconnecting said driving means withsaid power supplying means to permit the selective supply of electricenergy to said driving means; actuating means for actuating said drivingmeans through said switching means, said actuating means includingpermanent magnet means, electromagnetic means and control means forcontrolling the electric energy supply to the electromagnetic means; andblocking means actuatable by said actuating means and engageable with atleast a portion of said shutter means to fix the shutter means at apredetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; said blocking meansbeing moved, when continuous shooting, into said second rest positionthereof, and being maintained at said second rest position even afterthe electric energy supply from said power supplying means is stopped bysaid control means, thereby permitting the continuous operaTion of saidshutter means.
 5. In a photographic camera capable of continuousshooting, a combination comprising: shutter means rotatable from apredetermined position for exposing a film; driving means for rotatablydriving said shutter means, power supplying means operatively connectedto said driving means for supplying electric energy thereto; said powersupplying means including a storage battery, switching means arrangedbetween said driving means and said power supplying means, saidswitching means connecting and disconnecting said driving means withsaid power supplying means to permit the selective supply of electricenergy to said driving means; actuating means for actuating said drivingmeans through said switching means, said actuating means includingpermanent magnet means, electromagnetic means and control means forcontrolling the electric energy supply to the electromagnetic means; andblocking means actuatable by said actuating means and engageable with atleast a portion of said shutter means to fix the shutter means at apredetermined position thereof, and having a first rest position forstopping the movement of said shutter means and a second rest positionfor releasing the movement of the shutter means; said blocking meansbeing moved, when continuous shooting, into said second rest positionthereof, and being maintained at said second rest position even afterthe electric energy supply from said power supplying means is stopped bysaid control means, thereby permitting the continuous operation of saidshutter means.
 6. In an electromagnetic shutter release control devicefor use with a motion picture camera, a combination comprising: shuttermeans rotatable from a predetermined position for exposing a film;driving means for rotatably driving said shutter means; power supplyingmeans operatively connected to said driving means for supplying electricenergy thereto; release switch means movable between an OFF position andan ON position for turning the camera into operating condition inresponse to a shutter releasing operation of said camera; switchingmeans arranged between said driving means and said power supplying meansfor connecting and disconnecting said driving means with said powersupplying means to permit the selective supply of electric energy tosaid driving means; a movable member operatively engageable with saidswitching means for actuating said driving means; actuating means foractuating said movable member to activate said switching means, saidactuating means including permanent magnet means and electromagnetmeans, and said electromagnet means, when energized by said powersupplying means, actuating said movable member by interaction betweenthe electromagnetic field provided by said electromagnet means and themagnetic field by said permanent magnet means; blocking means actuatableby said actuating means and engageable with at least a portion of saidshutter means to fix the shutter means at a predetermined positionthereof, and having a first rest position for stopping the movement ofsaid shutter means and a second rest position for releasing the movementof the shutter means; and an electromagnetical control circuitcontrolling the direction of the current through said electromagneticmeans so that when said blocking means is moved from said first restposition thereof to said second rest position thereof, the current flowsthrough said electromagnetic means in a first direction, and when saidblocking means is moved from said second rest position thereof to saidfirst rest position thereof, the current flows through saidelectromagnetic means in a second direction opposite to said firstdirection, thereby changing the polarity of the magnetic poles of saidelectromagnetic means; said blocking means being moved, whencontinuously shooting, into second rest position thereof by the movementof said movable member, and being maintaIned at said second restposition even after the electric power supply from said power supplyingmeans is stopped by said control circuit means, thereby permitting thecontinuous operation of said shutter means.
 7. A combination as definedin claim 1, wherein said blocking means includes a stopper membermovable by the interaction of said permanent magnet means and saidelectromagnetic means engageable with at least a portion of said shuttermeans.
 8. A combination as defined in claim 1, wherein said shuttermeans includes a cam member engageable with said blocking means forstopping the shutter means precisely at said predetermined position. 9.A combination as defined in claim 6, wherein said electromagnetic meansfurther comprises two coils wound substantially at the same place forflowing a respective opposite-directional current therethrough tomagnetize said electromagnetic means.
 10. In an electromagnetic shutterrelease control device for use with a motion picture camera, acombination comprising: shutter means rotatable from a predeterminedposition for exposing a film; driving means for rotatably driving saidshutter means; power supplying means operatively connected to saiddriving means for supplying electric energy thereto; switching meansarranged between said driving means and said power supplying means forconnecting and disconnecting said driving means with said power supplymeans to permit the selective supply of electric energy to said drivingmeans; release switch means movable between an OFF position to an ONposition for operating the camera; a movable member operative engageablewith said switching means for actuating said driving means; actuatingmeans for actuating said driving means through said switching means,said actuating means including permanent magnet means andelectromagnetic means having a pair of coils wound around a softmagnetic material, and said electromagnet means, when energized by saidpower supplying means, actuating said movable member by interactionbetween electromagnetic field provided by said electromagnet means andmagnetic field by said permanent magnet means; blocking means actuatableby said actuating means and engageable with at least a portion of saidshutter means to fix the shutter means at a predetermined positionthereof, and having first rest position for stopping the movement ofsaid shutter means and second rest position for releasing the movementof the shutter means; and control circuit means including a firstcapacitor-resistor combination, a first transistor for adjusting thesupplying time of electric current to one of said coils, the inputvoltage of said first transistor being controlled by said firstcapacitor-resistor combination, a second capacitor-resistor combinationand a second transistor for adjusting the supplying time of the electriccurrent to another one of said coils, the input voltage of said secondtransistor being controlled by said second capacitor-resistorcombination; said blocking means being moved, when continuous shooting,into said second rest position thereof by energization of said firstcoil, and being maintained at said second rest position even after theelectric energy supply from said power supplying means is stopped bysaid control circuit means, thereby permitting the continuous operationof said shutter means.
 11. In an electromagnetic shutter release controldevice for use with a motion picture camera, a combination comprising:shutter means rotatable in either direction from a predeterminedposition for exposing a film; driving means for rotatably driving saidshutter means; power supplying means operatively connected to saiddriving means for supplying electric energy thereto; switching meansarranged between said driving means and said power supplying means, saidswitching means connecting and disconnecting said driving means withsaid power supplying means to permit the selective supply oF electricenergy to said driving means; electromagnet means for selectivelyactuating said switching means for energizing said driving means inresponse to a shutter rlease operation of said camera; control circuitmeans for controlling said electromagnet means, said control circuitmeans including a pair of capacitor-resistor combinations, a pair oftransistors, the input voltages of said transistors being controlled bysaid capacitor-resistor combinations, respectively, and selector switchmeans for controlling the introduction of said pairs into said circuit;and blocking means actuatable by said electromagnet means through saidcontrol circuit means for blocking said shutter means in eitherrotational direction thereof, said blocking means having a first restposition for maintaining said switching means at non-actuated conditionthereof and stopping the rotational movement of said driving means ineither direction, and a second rest position for maintaining saidswitching means at actuated condition thereof and releasing therotational movement of said driving means in either direction, saidblocking means further comprising a movable portion which is movableinto and out of at least a portion of the locus of the rotation of saidshutter means , said shutter means having a rotatable portion engageablewith said movable portions, thereby stopping the rotational movement ofsaid shutter means in either direction when said two portions are movedto engage each other.
 12. In an electromagnetic shutter release controldevice for use with a motion picture camera, a combination comprising:shutter means rotatable from a predetermined position for exposing afilm; driving means for said shutter means; power supplying meansoperatively connected to said driving means for supplying electricenergy thereto; switching means arranged between said driving means andsaid power supplying means for connecting and disconnecting said drivingmeans with said power supplying means to permit the selective supply ofelectric energy to said driving means; electromagnetic means forcontrolling said driving means through said switching means; engagingmeans rotatable integrally with said shutter means; blocking meansincluding a first movable member and a second movable member; andcontrol circuit means having a timing circuit for controlling theenergization of said electromagnetic means, said control circuit meanspermitting, when said switching means is changed from a first positionthereof to a second position thereof, electric current through saidelectromagnet means in the direction to actuate said first movablemember, and while said second switch is subsequently maintained at saidsecond position thereof, stopping said electric current through saidelectromagnet means after an elapse of time determined by said timingcircuit, and when said switching means is returned from said secondposition to said first position, permitting electric current throughsaid electromagnet means in the direction opposite to said direction.13. In a motion picture camera, an electromagnetic shutter releasingdevice for electromagnetically releasing a movable shutter from its restposition to expose a film through an aperture and for stopping theshutter at a predetermined position at the end of the exposure, saiddevice comprising: shutter means; driving means for said shutter means;power supplying means operatively connected to said driving means forsupplying electric energy thereto; switching means arranged between saiddriving means and said power supplying means, said switching meansconnecting and disconnecting said driving means with said powersupplying means to permit the selective supply of electric energy tosaid driving means; electromagnetic means connected to said powersupplying means through said switching means and magnetizable withopposite polarities in response to the changes in the direction of thecurrent through said electromagnetic means; permanent magnet meanslocated adjacent said electromagnetic means to interact with theelectromagnetic means; controlling means for controlling the movement ofsaid shutter means, said controlling means having a member movable bythe interaction of said electromagnetic means and permanent magnetmeans, said movable member being movable between a first position forstopping the rotational movement of said shutter means and a secondposition for permitting the rotational movement of said shutter means;and said movable member being moved, when continuous shooting, into saidsecond position thereof, and being maintained at said second positioneven after the electric energy supply from said power supplying means isstopped, thereby permitting the continuous operation of said shuttermeans, adjusting means operatively connected to said movable member foradjusting the attracting force caused by the interaction of saidelectromagnetic means and said permanent magnet means, said adjustingmeans including an adjustably contacting member to said movable member,and a setting member to adjustably set said contacting member thereby toenable said electromagnet means to move said movable member onlysupplying a small current to the electromagnetic means.
 14. In anelectromagnetic shutter release device for use with a motion picturecamera being selectively capable of a single frame exposure and acontinuous filming, said device having at least one magnetic circuitincluding a permanent magnet and an electromagnet, an improvementcomprising: permanent magnet means; electromagnet means interacting withsaid permanent magnetic means; power supplying means for actuating saidelectromagnet means; movable means driven by the magnetic interaction ofsaid permanent magnet means and said electromagnet means,; shutterrelease means movable between a first position for releasing the shutterand a second position for stopping the shutter; said movable meanshaving a first position for maintaining said shutter release means inits second position for stopping the shutter and a second position forreleasing said shutter release means to release the shutter, saidmovable means being moved, when continuous shooting, into said secondposition thereof, and being maintained at said second position evenafter the electric energy supply from said power supplying means isstopped, thereby permitting the continuous operation of said shutter,switch means actuatable by said movable means when the latter ispositioned at its extreme position; and adjusting means for reducing theinteraction forces of said electromagnet means and said permanent magnetmeans, said adjusting means including two independently operableadjusting members, one of which operates to reduce the attractive forcebetween said two magnet means in a direction in which said switch meansis actuated and the other of which operates to reduce the attractiveforce in the opposite direction thereby to enable to move said movablemeans with a small current supplied to said electromagnet.